What are the other Names for this Condition? (Also known as/Synonyms)

• Atypical Pneumonia caused by Chlamydia Pneumoniae Infection
• Chlamydophila Pneumoniae Infection 
• Community-Acquired Pneumonia caused by Chlamydia Pneumoniae Infection

What is Chlamydia Pneumoniae Infection? (Definition/Background Information)

• Chlamydia Pneumoniae Infection is a common bacterial infection of the airways. It is one of the most common causes of atypical pneumonia (lung infection) in the community. The infection is mild in a majority of individuals, but can be severe and fatal if neglected in individuals at risk
• The disease most commonly spreads from one infected individual to another by breathing in of the cough or sneeze droplets released in air. The signs and symptoms usually develop after a long incubation period of 3-4 weeks after exposure to the bacteria
• Nearly 70% of the infected individuals are asymptomatic or present with mild to moderate symptoms of upper airway illness such as throat or ear/sinus infection. The remaining 30% can develop lung infections leading to atypical pneumonia that can rarely become severe, particularly in the elderly and immunocompromised individuals
• In addition to respiratory illnesses, Chlamydia Pneumoniae Infection is also associated with chronic conditions, including chronic diseases of the lungs (such as asthma, chronic obstructive pulmonary disease, and lung cancer), neurological disorders (such as Alzheimer's disease, multiple sclerosis, and schizophrenia), as well as atherosclerosis (narrowing of blood vessels due to deposition of cholesterol), and arthritis (swelling of the joints)
• The healthcare professional should have a high index of suspicion for Chlamydia Pneumoniae Infection. This is especially important since the signs and symptoms may not be very prominent and distinguishable from other causes of atypical pneumonia. The recommended diagnostic test for this infection is the serological test ‘ELISA’ that helps detect antibodies against Chlamydia pneumoniae
• Antibiotic therapy is typically the main course of treatment. Since, a definitive diagnosis takes time, in order to avoid delay in treatment, empirical antibiotics are started on the initial suspicion of atypical pneumonia
• In a majority of individuals, Chlamydia Pneumoniae Infection resolves without any complications, and a complete recovery is observed within about 2 weeks. Presently, there is no vaccine available for this bacterial infection

Who gets Chlamydia Pneumoniae Infection? (Age and Sex Distribution)

• Chlamydia pneumoniae is a type of bacteria that commonly causes infection of the airways
• It is widespread and is estimated to infect around 80% of the people by the time they reach 60-70 years of age
• The infection is seen worldwide among all races and ethnic groups and can occur at any age with no seasonal variation noted
• Both males and females are affected

What are the Risk Factors for Chlamydia Pneumoniae Infection? (Predisposing Factors)

Chlamydia Pneumoniae Infection is a common respiratory infection. The risk factors for the Infection include:

• Chronic smoking, since smoking affects the immune system of the lungs
• Individuals with chronic illnesses and those who have weakened immune systems
• Chronic steroidal therapy and immunosuppressive therapy
• Overcrowded conditions: The disease spreads more easily in closed and ill-ventilated spaces such as dormitories, military barracks, prisons, etc.

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Chlamydia Pneumoniae Infection? (Etiology)

• Chlamydia Pneumoniae Infection is caused by a parasitic bacterium that infects and multiplies in the lining of the airways including the throat, windpipe, and lungs
• It can spread from one individual to another in the following manner:
  • By breathing in the infected air droplets which are created when an infected individual coughs or sneezes
  • On touching things that are contaminated with droplets from such infected individuals and then touching one’s mouth or nose (with the unwashed hands)
• It usually requires 3 to 4 weeks to develop the symptoms after exposure to Chlamydia pneumoniae

In general, individuals with Chlamydia Pneumoniae Infection often have mild signs and symptoms. They are able to carry on with their daily activities without much difficulty. 

What are the Signs and Symptoms of Chlamydia Pneumoniae Infection?

• In the majority of people, Chlamydia Pneumoniae Infection is asymptomatic or presents with mild to moderate illness of the upper airways such as throat infection or ear/sinus infection. The signs and symptoms may include:
  • Fever (low-grade)
  • Headache
  • Runny or stuffy nose
  • Tiredness
  • Hoarseness of voice
  • Throat pain
  • Cough that can last for weeks or months
• Infection of the lower airways may cause bronchitis (swelling of the airways that carry air to the lungs)
• In some individuals, C. pneumoniae can cause pneumonia (lung infection), which starts with certain non-specific symptoms of upper airway infection followed by mild symptoms of atypical pneumonia in the next 1-4 weeks. They are able to carry on with their daily activities without much difficulty
• Typically, pneumonia is characterized by:
  • Cough that persists for several weeks
  • Shortness of breath
  • Muscle pain in the chest due to coughing
  • Non-specific symptoms such as loss of appetite, nausea, stomach upset, body pains, rash, etc.
• Older adults and immunocompromised individuals are at risk for a severe disease that may cause respiratory failure, drowsiness, or altered sensorium
• Infections of other organs can also occur but are less common. These include:
  • Endocarditis, myocarditis, and pericarditis: Swelling of heart and its lining
  • Encephalitis and meningitis: Swelling of the brain and its coverings

How is Chlamydia Pneumoniae Infection Diagnosed?

The healthcare professional should have a high index of suspicion for Chlamydia Pneumoniae Infection. This is especially important since the signs and symptoms may not be very prominent and distinguishable from other causes of atypical pneumonia.

The following methods may be used to diagnose the lung infection:

• A thorough physical examination and complete medical history
• Chest X-ray may reveal the presence of pneumonia
• Arterial blood gas indicates the level of oxygen in blood
• Complete blood count (CBC) test may reveal an increased, normal, or decreased number of white blood cells
• Sputum culture and blood cultures help determine the cause of pneumonia. The healthcare provider needs to communicate with the laboratory about the suspicion of Chlamydia Pneumoniae Infection. This is especially important since the bacteria causing the infection requires special testing procedures in the laboratory
• The diagnostic test of choice for this infection is the serological test ELISA, which helps detect antibodies against Chlamydia pneumoniae
• A bronchoscopy may be needed to help rule out other causes of pneumonia
• CT scan of the chest is also helpful in determining the extent of pneumonia
• In severe and rare cases, an open lung biopsy may be performed to exclude other causes

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Chlamydia Pneumoniae Infection?

In the majority of people, Chlamydia Pneumoniae Infection is mild and resolves without causing any significant complications. However, in others, the complications may include:

• Worsening of asthma
• Respiratory failure
• Spread of infection from the lungs to other organs causing:
  • Myocarditis: Swelling in the heart
  • Encephalitis: Swelling in the brain, which can cause severe headaches and confusion

In addition to respiratory illnesses, Chlamydia Pneumoniae Infection is also associated with certain chronic conditions as follows:

• Chronic diseases of the lungs, such as asthma, chronic obstructive pulmonary disease, and lung cancer
• Neurological disorders, such as Alzheimer's disease, multiple sclerosis, and schizophrenia
• Atherosclerosis
• Arthritis

How is Chlamydia Pneumoniae Infection Treated?

The following treatment measures are generally used to treat Chlamydia Pneumoniae Infection:

• Antibiotic therapy is typically the main treatment course followed. A definitive diagnosis takes time; therefore, to avoid delay in treatment, empirical antibiotics are started on the initial suspicion of atypical pneumonia
• Symptomatic treatment measures may be used to alleviate pain and other symptoms of the infection
• Over-the-counter medication for fever and cough can help improve one’s symptoms. It is important to note that taking over-the-counter medications should only be after due consultation with the healthcare professional
• Plenty of rest and intake of fluids can help in a speedy recovery
• In severe cases of infection, hospitalization for administration of intravenous antibiotics and oxygen treatment may be necessary

How can Chlamydia Pneumoniae Infection be Prevented?

There is no vaccine currently available against Chlamydia Pneumoniae Infection. However, the following preventative measures can help arrest the spread of the infection:

• Frequently washing one’s hands thoroughly with soap and water
• Covering one’s mouth and nose while sneezing or coughing
• Avoiding touching one’s face with unwashed hands
• Avoiding contact with individuals affected by the condition where possible. This also includes avoiding visiting them in hospitals

Such measures help decrease the spread of infection within the community.

What is the Prognosis of Chlamydia Pneumoniae Infection? (Outcomes/Resolutions)

In the majority of individuals, Chlamydia Pneumoniae Infection resolves without any complications, and a complete recovery is observed within about 2 weeks.

• Nevertheless, dry cough and general weakness can persist for a few weeks even after treatment
• Older adults and immunocompromised individuals are at risk for severe disease, which if neglected, can lead to complications that can even be fatal. However, early diagnosis, complete rest, and appropriate antibiotic treatment result in excellent prognoses

Additional and Relevant Useful Information for Chlamydia Pneumoniae Infection:

It is important to differentiate Chlamydia Pneumoniae Infection from other types of pneumonia. The concerned healthcare provider will determine the cause and type of pneumonia through appropriate testing.

Other clinical conditions which can present with similar signs and symptoms include the following:

• Bacterial pneumonia
• Fungal pneumonia
• Viral pneumonia
• Tuberculosis
• Influenza

The following article links will help you understand atypical pneumonia:

http://www.dovemed.com/diseases-conditions/atypical-pneumonia/